Weed management in direct seeded rice and Brahmi intercropping system in rotation with zero-till wheat
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Date
2017-07
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The above study was conducted at N.E.Borlaug Crop Research Centre, G.B.Pant University of Agriculture and Technology, Pantnagar (Uttrakhand) during two consecutive years (2015-16 and 201617). The experiment was set out in randomized block design with three replications. Total ten treatments allocated to direct seeded rice and brahmi intercropping were (1) 1:1 pendimethalin as pre-emergence (2) 1:1 pendimethalin fb twice hand weeding at 30 and 45 DAS/DAP (3) 1:1 pendimethalin fb cyhalofopbutyl supplemented with hand weeding at 45 DAS/DAP (4) 1:1 weedy check (5) 2:1 pendimethalin as pre-emergence (6) 2:1 pendimethalin fb twice hand weeding at 30 and 45 DAS/DAP (7) 2:1 pendimethalin fb cyhalofop-butyl supplemented with hand weeding at 45 DAS/DAP (8) 2:1 weedy check (9) sole rice (10) sole brahmi.
Results revealed that among various treatments, paired series (2:1) of direct seeded rice and brahmi along with pendimethalin as pre emergence fb cyhalofop-butyl as post emergence fb one hand weeding at 45 DAS was found superior in terms of reduction in total weed density and dry matter accumulation of weeds and also higher WCE. Sole rice (pendimethalin fb cyhalofop-butyl fb hand weeding at 45 DAS/DAP) recorded highest value for growth parameters, yield attributes, grain yield (5.30 and 6.56 t/ha in 2015-16 and 2016-17) followed by paired ratio (2:1) along with pre and post-emergence herbicide supplemented with hand weeding at 45 DAS (4.81 and 5.75 t/ha in 2015-16 and 2016-17) over all the treatments. Sole brahmi (3 hand weeding at 30,45 and 60 DAP) recorded maximum dry herbage yield (2.07 and 2.35 t/ha in 2015-16 and 2016-17, respectively) followed by alternate row (1:1) ratio along with pendimethalin as pre emergence fb cyhalofop-butyl as post emergence supplemented with one hand weeding at 45 DAP (2.00 and 2.12 t/ha in 2015-16 and 2016-17, respectively).
Maximum value of intercropping parameters viz., LER, ATER, RCC, Aggressivity, RYT and competition ratio were recorded in paired (2:1) ratio along with sequential application of pendimethalin as pre fb cyhalofop-butyl as post supplemented with one hand weeding at 45 DAS/DAP. Significantly higher value of soil N, P, K content and enzyme activity (viz., urease, dehydrogenase, acid phosphatase and alkaline phosphatase) were recorded in sole brahmi (3 hand weeding at 30,45 and 60 DAP) during both the years. The higher benefit cost ratio (9.41 and 11.07 in 2015-16 and 2016-17, respectively) were registered in alternate (1:1) ratio along with sequential application of pendimethalin fb cyhalofop-butyl fb one hand weeding at 45 DAS/DAP.
Significant differences were observed in total weed density and dry weight and WCE in succeeding zero-till wheat which were treated by various combination of herbicides during previous year in rice+brahmi intercropping treatments. Highest WCE was recorded in sole brahmi (3 hand weeding at 30,45 and 60 DAP) which was significantly superior than other treatments during both the years. Highest value of yield attributes and grain yield (5.20 and 5.50 t/ha in 2015-16 and 2016-17, respectively) of wheat was recorded in sole wheat which was at par with both row ratios along with sequential application of pendimethalin fb cyhalofop-butyl fb hand weeding at 45 DAS while brahmi dry herbage yield (1.87 and 1.80 t/ha in 2015-16 and 2016-17, respectively) was significantly superior than other treatments during both the years. Higher benefit cost ratio in succeeding zero-till wheat was found in alternate ratio of 1:1 (8.46 and 8.76 in 2015-16 and 2016-17,respectively) as compared to 2:1 series of rice and brahmi and sole crop of rice and brahmi.
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